Additive manufacturing (also known as 3D printing) is changing the manufacturing world by allowing parts to be printed one layer at a time. A variety of different types of 3D printers and printed materials are emerging and currently under development. This includes a variety of 3D printers using different materials including both polymers and metals. No 3D printing of superhydrophobic materials or parts currently exists. The reason has to do with current superhydrophobic technologies being strictly a surface phenomenon. That is, currently superhydrophobic coatings are produced by nanopatterning or nanotexturing a hydrophobic surface, while 3D printing is a volumetric process of printing parts layer upon layer, one layer at a time. Hydrophobic surface chemistry and nanotextured or nanoporous surface topography creates a pinned thin layer of air on the surface which results in superhydrophobic (extreme water repellant) behavior. Anything below the surface tends to have no effect on the surface's behavior. If the surface is damaged in any way, the pinned air layer goes away and the surface's superhydrophobic behavior is destroyed. Since 3D printing is a volumetric technology without any surface nanotexturing ability, it tends to be incompatible with standard superhydrophobic technologies.
Curing as used herein can be defined as any process where heat or radiation is used to catalyze or initiate chemical and molecular-level structural changes in a polymeric material such as epoxies, phenolics, polyesters and silicones. This type of curing is a term in polymer chemistry and process engineering that refers to the toughening or hardening of a polymer material by cross-linking of polymer chains (polymerization), brought about by, heat or chemical additives. When the additives are activated by ultraviolet radiation, the process is called UV cure. The term polymer as used herein is a large molecule consisting of many repeating subunits. Resin is defined as a solid or viscous material which gives or become a polymer after curing.
One material used for 3D printing parts is Ultra-Violet (UV) curable liquid resin, where a 3D printer either extrudes a liquid resin through an orifice into a UV flooded compartment containing the part being printed, or an entire layer of liquid resin is imaged with UV light at a time. The ultraviolet radiation causes the resin to partially cure (harden) such that it forms a printed part layer. Additional layers are printed, one at a time. The result of printing multiple 2D layers is a 3D composite printed part. A 3D printing process that produced superhydrophobic printed part behavior would be a new capability of 3D printing and would likely advance superhydrophobic technology usage.